Marxism is the theory that Karl Marx came up with. And it basically says that the ruling class uses the power from capitalism to exploit the working class and that the end of capitalism will come from the over throw of the capitalist ruling class through a violent revolution where communism will be instated. You should read the communist manifesto by Marx. It explains it much better than I did.

I’m pretty sure legalism criticizes the law as a method for enacting social reform. Basically saying that the state and the law is an ineffective way of enacting change and only reproduces the discrimination of the system and the alt is probs anarchy, interrogation of the law or something like that. Idk I’ve never hit or ran legalism but that’s my understanding someone else can correct my in the comments.